A Long Term Evolution (LTE) (Non-patent document 1) was standardized for the purpose of attaining a much faster data rate and decreasing a delay in a UMTS (Universal Mobile Telecommunications System) network. LTE-Advanced (also termed LTE Rel.10-12) was standardized aiming at attaining a much broader band and greater acceleration than LTE, and an examination of a succeeding system (called LTE Rel.13, 5G (5th generation mobile communication system)) is underway.
According to LTE Rel.8-12, a TTI (Transmission Time Interval) applied to DL (DownLink) transmission and UL (UpLink) transmission between a wireless base station and user equipment (UE) is 1 ms. The TTI in an LTE system (Rel.8-12) is also called a subframe length.